Preparation

For saffron chicken broth:
Bring all ingredients to boil in very large pot. Reduce heat to medium-low, partially cover, and simmer 2 hours, stirring occasionally. Strain broth into another pot. Spoon 1/4 cup fat from top of broth and place in medium bowl; add 1/4 cup broth. Cool fat mixture and reserve for matzo balls. Remove enough meat from chicken wings to measure 1 generous cup. Finely mince chicken; reserve for matzo balls. Chill remaining broth until ready to use. (Can be made 2 days ahead. Cover and keep chilled.)

For matzo balls:
Whisk eggs, salt, and pepper into chicken fat mixture. Mix in matzo meal, then spinach and reserved minced chicken. Cover and chill until firm, at least 1 hour and up to 1 day.

Bring large pot of generously salted water to boil. Using wet hands and about 2 tablespoons for each, shape matzo mixture into 16 balls; drop into boiling water. Reduce heat to low, cover pot, and simmer until tender, about 45 minutes. Using slotted spoon, transfer matzo balls to 13x9x2-inch dish. (Can be made 1 day ahead; chill.)

Skim any fat from top of broth; bring to simmer. Season with salt and pepper. Add cooked matzo balls; simmer until heated through, about 10 minutes. Ladle broth and 2 matzo balls into each of 8 bowls and serve.